


A Sansational SNAFU

by knowmeknot



Category: Undertale (Video Game)
Genre: Biting, Bodyswap, Double Penetration, Ecto-Genitalia (Undertale), M/M, Praise Kink, Spanking, Threesome - M/M/M, Vaginal Fingering, Voyeurism, dom berry, lewdberry
Language: English
Status: Completed
Published: 2020-01-13
Updated: 2020-01-13
Packaged: 2021-02-27 09:41:24
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 6,000
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22235008
Author URL: https://archiveofourown.org/users/knowmeknot/pseuds/knowmeknot
Summary: After a night of drinking and fun at the annual holiday party, Red, Blue and Sans find themselves waking up in each other’s bodies. They only need to pretend to be the other until they get this all sorted out. Easy enough… right?
Relationships: CherryBerry, ClassicBerry, Kustard, Sans/Sans (Undertale), Sans/Sans/Sans, sanscest
Comments: 4
Kudos: 93





	A Sansational SNAFU

**Author's Note:**

  * For [saturnwonder](https://archiveofourown.org/users/saturnwonder/gifts).



> Hi Saturn! I was your secret santa! :3 You wanted some bodyswap shenanigans, you got some! 
> 
> Just as a note any time a name is denoted with " " (e.g. "red" or "blue"), it means that it's the person in the other's body. Hope that'll clear any confusion near the last part.

A white ceiling littered with holes. That was what Red should’ve woken up to; instead, baby blue walls and a ceiling full of stars surrounded him. This wasn’t how his room should look. And why was he on an actual bed. With soft, white sheets? Why was he—

“WHA—?” 

Red raised his arms, gaping at his hands. His phalanges, which were normally sharpened like claws, were blunt. He sprung up and stared at himself in the mirror. 

“WHAT THE FUCK?!”

A pair of bright blue eye lights stared back at him. The scar on his left temple was gone. In fact, there wasn’t a single mark on his smooth, baby-faced skull. And his teeth! His teeth were not intimidating at all!

“WHY DO I LOOK LIKE BLUEBERRY? AND WHY DO I TALK IN ALL CAPS?”

Even his voice came out softer, lacking its usual harsh gravelly snarl. How could this have happened? What even happened. He last remembered being at the annual holiday party.

_Red took another swig of the dark amber liquid, sighing deeply at the burn as it traveled down his conjured throat. Without warning, it was snatched clean out of his hands._

_”RED! THIS IS YOUR FIFTH DRINK! DON’T YOU THINK THAT’S ENOUGH DRINKING FOR ONE NIGHT?” Blue held the glass above his head in his left hand while his right rested on his hips._

_“but i wanna!” Red whined, stomping his foot like a babybones throwing a temper tantrum._

_“WHERE DID YOU EVEN GET THIS? I THOUGHT I CUT YOU OFF!”_

_“alphys’ a pal, som’times,” Red shrugged._

_He swayed slightly on his feet. He gazed, with dilated pupils, at the drink in Blue’s hands. He saw Blue’s expression scrunched into a pout. It was so cute when Blue pouted, with his cheeks puffed out and bone brows furrowed downwards._

_Without thinking, Red stumbled to his nicer counterpart. Blue stood his ground despite Red towering a head taller than him._

_Damn, Blue was so cute._

_Red leaned down and pressed his teeth against Blue’s._

“FUCK!” Red snarled as he face planted onto the carpeted floor, creating a dull thud. 

How could he allow his inhibitions to let loose so much that he’d fucking kissed Blue of all monsters?! The only option worse was if he’d kissed Sans. No wait, both were equally bad since he was equally in love with both of them. And they were dating each other.

“WHAT THE FUCK WAS I THINKIN’! ‘M NEVER GETTIN’ DRUNK AGAIN!”

Despite Red’s wish to reset time to make the kiss never happen, he couldn’t help but be curious. Perking back up from his pathetic puddle on the carpet, Red strolled in front of the mirror. He peered behind his back twice, fiddling with the edges of the soft pajama shirt. Bright yellow stars decorated the attire. In one fell swoop, he lifted the shirt and stared at his reflection in the mirror.

Holy shit! Blue looked like this?! 

Red turned around, admiring the pristine white bones, not a single scar or chip in sight. They had a healthy, pearly gleam too. Red stroked the bottom-most rib and shuddered, closing his eye sockets.

Damn, it felt so good. His fantasies of Blue were becoming true! Even if this was undoubtedly not the way he imagined experiencing them. Fuck, this was creepy as fuck!

“what are you doing bro?” A dry voice came from behind him. “didn’t strike you as vain.”

“MIND YE— AR.”

“what?”

“MINDFULNESS YEAR! IT’S TO MAKE SURE MY BODY IS WELL AND HEALTHY! HEH HEH!” 

Sweat coalesced on the back of Red— or Blue’s— skull as Blue’s brother narrowed his eye sockets in suspicion. The orange-donned bean pole chewed on the lollipop in his jaw.

“ok, bro, if you say so. you woke up later than usual.” Stretch scratched the back of head.

“THE HOLIDAY PARTY TIRED ME OUT!”

Stretch’s eye sockets lidded as a smirk crept onto his expression, “i’m sure you had a good time.”

“YEP THE BEST, MWEH HEH HEH.”

Stretch raised a bone brow, growing ever more suspicious. Red was sweating bullets. He even laughed like Blue this time! What was this dude’s problem? 

Unable to stand the building tension any longer, Red spun around and made to get changed, hoping that this lanky brother of Blue would fuck off already. 

Instead, Stretched stated casually, “by the way, when’re you heading off to your date with sans?”

Red luckily held back his sputtered and simply halted in his tracks. 

Thinking fast, he blurted, “IN A FEW HOURS! I NEED TO SEE ALPHYS FIRST!”

There was a pause, before Stretched replied with a simple, “ok,” and left. Red let out a sigh of relief and quickly got dressed. 

Shit, he had a date with Sans? When was this? Should he shortcut over? Wait, did Blue even know how to use shortcuts like the rest of the normal Sanses?

“by the way, _bro_.”

“YE-AES?!” Red yelped.

“just give me a heads up when you leave so i can get the machine running.”

“YEP, SURE THING, BO--BRO!”

Stretch winked at Red and then left again. Standing in the middle of the room like an idiot, Red couldn’t help but wonder if he was found out already. If it were Boss, he would’ve been suspicious from the first word that left his mouth.

On his way out of the house, Stretch helpfully said, “alphy’s in waterfall, by the way,” with a smug smirk on his face. Red resisted the urge to wipe it off and simply gave his thanks. It wasn’t until Red made his way into Waterfall, and encountered a muscle-heavy Alphys wielding a giant axe that he’d realized what a huge mistake he’d made.

Red barely had time to react with a bone attack as Alphys swung the deadly weapon at his skull. Alphys roared, swatting away the bone attack like they were flies. Red attempted to shortcut, only to realize a second later that Blue couldn’t do it. It was too late to stop Alphys from body slamming into him.

“FUCK!” 

Alphys froze with her mouth and eyes wide open. 

“Blue, since when did you start cursing like that?!” 

With a grunt, he shoved Alphys off and stood back up, fixing the crooked blue bandana wrapped around his neck. It sure was soft. Just like the wearer. Red immediately shook the distracting thought from his mind.

Alphys stood up and narrowed her gaze, frowning deeply. 

“What’s up with you today? Where’s all your ENERGY!” Alphys slapped him hard across his shoulders.

Red reflectively almost swore again before he stopped himself. 

“NOTHING’S WRONG. I JUST REMEMBERED SOMETHING AT HOME. BYE!”

Before Alphys could stop him, Red took off in the opposite direction. It wasn’t until he was halfway through Waterfall that a realization came to him.

“WAIT, I HAVE A DATE WITH SANS?!”

\-----

“All, c’mon, Red, it’s been so long since we last fucked. Aren’t you feeling frisky lately?” Doggo whined. He slung an arm along Sans’s— or Red’s— shoulder and leaned heavily into his side.

Sans casually pushed the other away while picking up a wooden stick off the ground. 

“nah, not particularly, pal,” he said. 

Sans tossed the stick to his right. Doggo immediately perked up at the sudden movement and ran off into the direction of the flying stick. Sans gave a relieved sigh and slumped across his— no, his counterpart’s— sentry station.

That’s right, somehow he’d woken up to find himself, not only in Red’s universe, but also his body! He had no idea how or why, but he had an inkling that something happened during the holiday party. But what was it? He hadn’t even drank that much since that would’ve upset Blue; only enough to get lightly buzzed

_”why’s so blue, blue? heheh,” Sans chuckled at the blush adorning Blue’s skull. It was adorable. His datemate was simply the greatest._

_“NO-NOTHING! SIMPLY NOTHING AT ALL!”_

_Blue took a large swig from a large solo up in his hand and immediately scrunched his face in disgust._

_“HOW CAN YOU AND RED STAND THIS STUFF?! IT TASTES HORRID!” the smaller skeleton practically shoved the drink into Sans’s hands._

_“can’t be that bad.”_

_He gulped down a mouthful of the alcoholic drink. It stung a bit as his magic absorbed the liquid, leaving a strange tingling warmth within him. Blue stared at Sans, cheeks still dusted his namesake._

_“what’s got you all hot and bothered?” Sans smirked._

_“HOT AND BOTHERED? POSSIBLY THE ALCOHOL. OR MAYBE YOU.”_

_Blue walked up to Sans, stood on his tiptoes and kissed him._

Sans grinned at the memory of Blue’s kiss, phalanges absently stroking his teeth. He was ripped out of his daydream at the sound of sudden barking. 

Sans stood up to run, but didn’t make it far before Dogaressa caught sight of him. He cursed. 

This was the worst! He had expected Underfell to be “kill or be killed” like Red had professed many times. If that’s the case, then why the hell did Red sleep with so many members of the canine unit that they’re literally chasing after him (since he’d been stuck in Red’s body this morning)! 

Surely, the couple were an exception. They’d got to be.

“Ah, Red! Just the monster we were sniffling for!” Dogaressa exclaimed, bounding over.

Sans took a step back, and bumped straight into Dogamy.

“Hey, Red! Wifey and I are, y’know, getting a little _heated and close_ since it’s the holidays. We’re wondering if you want to join us in on the fun tonight.” Dogamy fucking winked at him!

Sans tried not to gape like a goldfish back at the canine couple.

“Yes, do join us, Red,” Dogaressa ran her front paw down Sans’s spine, causing him to shiver involuntarily. She leaned down and whispered, “We know you like it _ruff_.” Dogaressa giggled.

Sans would’ve laughed at the pun if it weren’t for the furry situation he was in. And it was all because of Red! The stupid, handsome idiot! That apparently flirted and fucked every member of the canine unit! If Red was that open, why hadn’t _he_ ever thought to sleep with Red?

Wait-- what was wrong with him?! Sure, Red was attractive, in a rugged, bad-boy type of way, but he was already with Blue. Which only made this whole canine-unit-offering-sex thing weird as all hell.

“WHAT ARE YOU TWO MUTTS DOING AWAY FROM YOUR POST?” A sharp voice snapped.

Red’s brother stood before them, arms crossed in front of his chest and sharp teeth in a deep frown.

“AND WHELP! YOU HAD BETTER NOT BE FLIRTING WITH THE CANINE UNIT AGAIN OR I WILL ADD ANOTHER SCAR ONTO YOUR SKULL!”

Edge McEdgelord marched over and yanked him up by the black collar around his neck.

“hey! leggo!” Sans attempted to kick out of Edge’s grasp, who tightened his grip.

“WELL, WHAT ARE YOU TWO GAWKING AT! LEAVE! GO FUCK YOURSELVES AND LEAVE MY BROTHER OUT OF THIS!”

Once the two royal guardsmen were gone, Edge turned his attention onto Sans, who leaned against a nearby tree, scrunching his face to look angry. Red’s brother narrowed his eye sockets, bone brows furrowed.

“what? cat-nine got yer tongue?”

Edge leaned down until his face was inches from Sans’s, who recoiled slightly.

“DID YOU SWALLOW A LEMON? WHY’S YOUR FACE ALL WRINKLED?”

“ _lime_ just sour from all this,” Sans quipped. 

Edge threw Sans a death glare, then stood up and turned away.

“LET’S GET HOME!”

The two stood there in silence, staring at each other. Beads of sweat formed on Sans’s skull. Edge cleared his throat, expression unimpressed. He sighed and, before Sans could react, lifted the smaller skeleton off the ground. Sans grumbled and crossed his arms like a petulant child as he was carried back to Red and his brother’s home.

At least it gave Sans time to process everything that’s happened this morning. So, he’d woken up in Red’s body for some reason, and once he stepped outside, was almost immediately chased after by each of the Royal Guard’s canine unit, who all invited him— Red— for a fuck. Sans didn’t know why but the thought of Red banging all those dogs bothered him.

Why should he care? Especially since he’s already with Blue!

Try as he might, Sans couldn’t deny the fact that he found Red attractive and has fantasized him, Blue and Red having a good time together. But it was too much work for him to think of a way to make it work. Besides, he was happy with what he currently had. Yep, no lingering regrets at all.

Sans snapped out of his thoughts at the sound of the front door opening. Edge dropped him unceremoniously on the floor. Before Sans could get up, however, gravity settled on his soul, trapping him against the carpet. Edge summoned a sharp bone construct, directing it at Sans’s ribs.

“WHO ARE YOU?”

“don’t know what yer talkin’ ‘bout, bro-oss!” Sans struggled against the blue magic. 

Edge scoffed and pressed the sharp bone a centimeter deeper. 

“YOU ARE NOT MY BROTHER! AND IT IS EXTREMELY OBVIOUS!” Edge smirked. “A BUDDING ACTOR SUCH AS MYSELF WOULD KNOW!”

“you act?”

“AS A HOBBY, YES! WAIT—! I RECOGNIZE THIS TACTIC. TRYING TO DISTRACT ME SO YOU CAN GET A SURPRISE HIT!” Edge added extra weight onto his soul, making it hard to breathe. “THE GREAT AND TERRIBLE EDGE WILL NOT BE FOILED BY YOUR DASTARDLY TRICKS! SO SPEAK, IMPOSTER, WHO ARE YOU AND WHY ARE YOU IN MY BROTHER’S BODY!”

Sans wheezed, “if i told ya i’m sans, and that i don’t know how, would ya believe me?”

Edge surveyed Sans for a beat. Moments later, to Sans’s surprise, the pressure relented. 

“wait, you actually believe me?”

Edge crossed his arms. “OF COURSE. ONLY YOU WOULD MAKE SUCH AWFUL PUNS. AND BE SUCH A PRUDE TOWARDS THE INVITATION OF CASUAL SEX.”

Sans sputtered, eye sockets wide as dinner plates. What the fu—! Since when does a Papyrus think like this?!

“IF YOUR WONDERING WHY I KNOW THIS, BLUE HAS TO TOLD ME.”

“blue told you?!”

“YES, WE GET ALONG DUE TO OUR MUTUAL INTEREST IN ACTING. AND COOKING. HE QUITE GOOD AT IT, THE ACTING I MEAN. BUT NOT AS GOOD AS THE GREAT AND TERRIBLE EDGE!”

The rest of Edge’s ramblings went ignored as Sans became a sad puddle in the carpet. 

He was a failure! He failed his mate! Why did Blue never bring it up with him? And it wasn’t like he didn’t want or like sex; hell, he enjoyed it immensely with Blue. He simply shied away from anything that wasn’t vanilla. Was Blue not happy with him about it? Was he too boring? Blue’s never made it an issue.

Two strong arms suddenly lifted Sans off the floor and plopped him onto the couch.

“AND NO, BLUE IS FINE WITH THAT.”

Sans opened his mouth.

“I CAN READ MY BROTHER LIKE A BOOK, WHICH IS WHY I KNOW WHAT YOUR THINKING.”

Sans closed his mouth, his teeth frowning as much as he could.

“ARE YOU POUTING?”

“no.”

“YOU ARE.”

“am not.”

“YOU ARE.”

“am too.”

“ARE NOT!”

“heh, gotcha.”

Edge screeched, ‘I’VE BEEN TRICKED BY YOUR WORDPLAY!” He then proceeded to tramp around the living space.

“so how’ja know i wasn’t your bro?”

The taller skeleton halted and turned back to Sans. He held his arms akimbo.

“WELL, IT’S HEAT SEASON FOR THE CANINE UNIT— THAT’S WHY THEY’VE BEEN HOUNDING YOU BY THE WAY— WHICH RED ALWAYS CONCEDED TOO EXCEPT FOR THE RECENT TWO YEARS!”

“guess i shouldn’t be surprised.”

“NO, YOU SHOULDN’T. HE LIKES IT _RUFF AND TOUGH_.”

“didja just pun?” 

“NOPE, YOU’D JUST IMAGINED IT. WIPE IT FROM YOUR MEMORY!”

“ok.”

“ANYWAY, YOU ALSO DIDN’T SHORTCUT US BACK WHEN I ASKED YOU TOO, WHICH MY BROTHER WOULD’VE.”

“red told you about that?”

Edge scoffed at Sans’s words.

“OF COURSE! KEEPING SECRETS AMONGST CLOSE FAMILY IS DANGEROUS IN OUR UNIVERSE. THOUGH I HAD TO RIPE IT OUT OF HIM AFTER I DISCOVERED THAT SECRET. THE ONLY OTHER SECRET THAT I HAD TO FORCE OUT OF HIM IS HIS CRUSH ON YOU AND BLUE--”

“wait, red- what?” 

Edge immediately clapped a gloved hand on his mouth.

“LET’S PRETEND YOU DIDN’T HEAR THE LAST PART. WIPE THAT FROM YOUR MEMORY AS WELL!”

How was he to feel about this? Excited? Warm? He definitely wasn’t upset. He might as well just admit to himself that he had feelings for Red just like he did for Blue.

And as if the universe were playing a prank, Sans suddenly remembered he had a date scheduled with Blue. But he was here, in Red’s body, in Underfell, and not back home.

“i gotta get back home!” He stood up.

Edge smirked, “OF COURSE! THE MACHINE IS IN THE BACK OF THE HOUSE. I’M SURE YOU KNOW HOW TO OPERATE IT!” 

Without another word, Sans got up and did just that. It wasn’t until he was being transported out of this universe that a realization dawned upon him.

“did i just get outplayed?”

\-----

_”IS IT READY?” Blue asked the Alphys wearing swirly glasses._

_The mad scientist gave a sharp grin as she handed over a vial containing a dark purple liquid._

_“Here you go. Three drops should do it, one for each of you.”_

_“THIS HAD BETTER NOT CAUSE ANY UNDUE HARM TO OUR BROTHERS OR I WILL HUNT YOU DOWN AND BREAK YOUR SPINE!” Edge warned with a low growl._

_“N-n-not at all. I, I would n-never!”_

_“AS IT SHOULD BE.”_

_Blue swished the substance within the vial, gazing at it with amazement. He couldn’t wait to use this! And the holiday party would be the best time._

_“you sure this is gonna work, bro?” Stretch asked, biting on the half eaten lollipop in his mouth._

_“YES, PAPY, I WILL MAKE IT WORK!” Blue replied._

_“I HAVE GREAT CONFIDENCE IN THIS PLAN OF OURS TO GET THEM TOGETHER!” Papyrus clapped his gloved hands together while beaming with excitement._

_“THEY BETTER STOP BEATING AROUND THE DAMN BUSH AND ADMIT THEIR FEELINGS,” Edge sighed with an eyeroll. He caught sight of Alphys scribbling furiously away in her notebook. “YOU HAD BETTER NOT BE WRITING— WHAT DO YOU CALL IT, FANFICTION?— OF MY BROTHER AGAIN!”_

_Alphys flinched at the accusation and had the decency to look apologetic. “O-of course n-not. It’s just my, my notes on the po-potion, sir.”_

_Blue carefully put away the vial into his inventory._

_“i still don’t think red is dateable, especially for someone as amazing as blue,” Stretch said._

_“NO ONE ASKED FOR YOUR SHITTY OPINION,” Edge snarled._

_“LANGUAGE!” both Blue and Papyrus admonished in unison._

_Blue continued, “IT IS MY CHOICE TO DATE WHO I WANT TO. BESIDES HIS LEWD JOKES AND ROUGH EXTERIOR, RED HAS BEEN VERY NICE WITH ME!”_

_“AND SANS WOULD NOT HAVE FALLEN FOR RED IF HE WERE A BAD MONSTER,” Papyrus added._

_“fine, fine, you two win. let’s hope this all works without a hitch.”_

_”SO HOW DO WE SWITCH BACK TO OUR ORIGINAL BODIES?” Blue asked Alphys._

_Alphys’s cheeks turned a bright pink as she squealed and clapped her claws together._

_”OUT WITH IT!” Edge snapped._

_”Y-you have to… have to, sh-share s-souls with one another!”_

Blue bounced where he stood, which happened to be behind Sans’s hotdog cart. There was a line of customers waiting. Blue preferred tacos, but he couldn’t even think about messing with Sans’s hotdog business; at least, not until they talked about it first.

“Thank you, Mr. Bones,” a little girl said as Blue handed her a hot‘dog’.

“no problem!”

Several seconds went by. The short little girl frowned.

“You didn’t tell me a new joke, Mr. Bones!”

“a joke, huh? uh, let’s see. the great and— i mean, i got one. what do you call a fake noodle?”

“Um, I don’t know…?”

“an impasta.”

For a moment, Blue thought he’d been found out, but then the little girl giggled. She gave her thanks and waved good-bye. Warmth blossomed within Blue’s soul. To know that Sans brought laughter to these kids had Blue smiling. He knew, despite how much he’d screech about the puns, that they made him laugh just the same.

After thirty more minutes, Blue was ready to close shop. He had a date to get ready for,after all. A date with himself times two, mweh heh heh. He couldn’t wait to see how this would play out. Although he hadn’t expected to switch bodies with his datemate, it probably worked out better this way. Being Sans for an afternoon definitely increase his appreciation for his boyfriend. 

Blue had walked to the park this morning but maybe he’d try to take one of those “shortcuts” back home. He closed his eyes and imagined Sans’s bedroom, trying to remember Sans’ explanation on how it was done.

In a blink of an eye and a sudden rush of dizziness, Blue stepped through a pitch black void and through a hole. He stumbled and fell out of the shortcut onto the cream carpet of Sans’ bedroom. 

“how can he stand for something this disorienting,” Blue commented.

Luckily, the carpet broke his fall. Blue peered around and then clicked his teeth at the disarray. Socks littered the floor, many of them not even paired! The trash tornado swished in its place in the back left corner of the bedroom. Sans had apparently brought up the treadmill from the Underground, though Blue’s never seen him use it. 

While waiting for Sans to show up, Blue kept himself busy with cleaning the dwelling. He didn’t have to wait long. Loud footsteps came up the stairs. It couldn’t have been Papyrus since he was out of town on a tour. The door burst open.

“WHAT THE HELL IS GOIN’ ON?” His own voice shouted at him.

Blue spun around. He’d never seen such an angry expression on his own face, what with his eye lights gone and two black sockets glaring back at him. 

“hi red.”

The other blinked. “YER NOT SANS.”

“what gave it away?”

“THE FACT YER CLEANIN’. AND SANS RARELY SAYS ‘HI’ AS A GREETING,” Red answered a matter-of-factly. “FOR SOMEONE WHO ACTS AS A HOBBY, YOU SURE NEED TO DO A BETTER JOB OF IT.”

Blue pouted, but then grinned. 

“well, i had to have been convincing during the holiday party to pull this whole scheme off! if you hadn’t drank that last cup on alcohol, you wouldn’t be in my body! bested by the magnificent blue! mweh heh heh!” 

As soon as those words left his mouth, a familiar magical signature filled the room. “Red” appeared between the two of them, surveying both of them.

“sup?”

“Blue” rolled his eye lights. “SEE, HE DOESN’T SAY ‘HI’ LIKE YOU DID.”

“i said hi?” Sans asked.

“this is getting confusing,” Blue commented.

“WAIT A SEC. YOU SAID YOU DID THIS ON _PURPOSE?_ ” “Blue” glared at Blue. “HOW?”

Blue fiddled with the zipper on Sans’s hoodie. “alphys came up with a body swap potion, and all three of us drank it, which is why we’re in each other’s bodies.”

Dead silence fell upon the room. 

“WHAT THE FUCK?! WHY?!”

“watch your language,” Blue scolded.

“FUCK LANGUAGE. WHAT PURPOSE DO YOU HAVE FOR THIS PRANK?!”

“yeah, would ‘preciate an explanation.”

Blue took a deep breath, trained his eyes on Sans, who gave him a bemused stare, and then Red, who was puffing out his cheeks in anger. It was adorable, but Blue already knew that. He smiled brightly at both his counterparts.

“sans, do you like red?”

“huh? uh, yeah, red’s a pretty swell pal.”

“no, i mean, like as in be attracted to and willing to be in a relationship with. please don’t lie.” Blue trained his sight back on his datemate, who stared back before giving a nervous shrug.

“ok, this is really freakin’ weird, seeing myself give me that look,” Sans turned to face “Blue”. “but yeah, i enjoy your company.” He winked for good measure.

“I DON’T UNDERSTAND WHAT THIS HAS TO DO WITH ANYTHIN’! THIS IS CREATIN’ A WHOLE LOTTA SHIT FER NOTH—”

Blue suddenly pressed his teeth against Red’s in the midst of his heated rant, complete shutting him up. Sans uttered a soft, “damn” that perfectly mimicked Red. 

When Blue pulled away, he saw his own face staring back at him, slack jawed and eye lights dilated.

“mweh heh heh, that’s payback for the kiss at the holiday party,” Blue teased. 

“you did what?” Sans asked.

“Blue” turned away, shoulders sagging. “YEAH, I WAS BEIN’ AN IDIOT DRUNK AND KISSED BLUE.”

Blue found it jarring to see such a sad and guilty expression on his own face. He was going to give himself a hug when Sans beat him to it.

“hey, it’s ok. like blue said earlier, we’re open to dating you if you wanna. no bones about it.” Sans leaned over to give a kiss of his own.

Blue didn’t interrupt as he watched “Red” make out with himself, enjoying the show with a lewd grin. He stuck a hand under Sans’s white shirt and tickled the insides of the bottom-most rib. Heat tingled from the area and spread throughout the rest of his bones.

It was convenient that he knew almost all of Sans’s weak spots. And this was the perfect opportunity to discover the others. It didn’t seem as though his partner even minded, given how Sans was trailing his phalanges along “Blue’s” lumbar region. “Blue” shivered and whined.

“gosh, this is so hot! you two totally meet the magnificent blue’s standards!”

Sans and Red finally broke apart with a string of saliva connecting the two of their mouths. Both of their cheeks flushed the respective color of their bodies’ magic. 

“my turn!” 

Blue inserted himself between the two skeletons and claimed his own mouth again. This time, he swiped a conjured tongue along the insides. To his surprise, Red responded by twirling a summoned tongue. Their appendages twisted and danced within their mouths. 

With a smirk, Blue snuck his wiggling hands into “his” pants, stroking at “his” pubis symphysis. Hearing his own wanton moans set him alight as magic pooled within “Sans’” pelvis. 

Red suddenly pulled away, gasping,” WAIT!”

Blue immediately pulled back, wondering if he was being too forward. Red took several deep breaths before he looked at Blue. Star-shaped pupils darted back and forth as he clenched his hands into fists.

“TH-THIS IS, THIS IS--” Red blushed.

“what is it?” Blue asked. “we can stop if you don’t want to do this anymore.”

“NO! IT’S NOT THAT. IT’S JUST-- I GET OFF MORE ON PAIN...” Red huffed. 

Blue and Sans gazed at each other before Sans scooted over to the bed, gave a nod and a thumbs up. 

“go for it, babe, have fun with him,” he said. “i’ll enjoy the show.”

Blue placed his hands both sides of Red’s skull. “hey, it’s ok red. i’ll be more than happy to do that. excited even! this is a great opportunity! do you prefer to be back in your own body? we only have to share souls together to turn back!” 

“NAH, I’M LIKIN’ THIS. IF SANS DOESN’T MIND.”

“i’m good. good opportunity for research, if ya know what i mean.” As emphasis, Sans scratched along “Red’s” collarbone, shivering violently. “just don’t do anything weird to my body and i’ll treat yours the same.”

“ALRIGHT.”

Blue gave a full-faced grin, pulling down the bright blue shorts and leggings he normally wore and jabbing at the holes on the back of “his” pelvis. Of course he knew all of his own pleasure spots, which had Red gasping and the magic solidifying.

“summon my ecto for me,” Blue commanded with a particularly sharp scratch of the pelvis.

“AH!”

Immediately, the light blue magic coalesced and covered the bones from the last rib downwards. Red had been clearly unprepared to have fully summoned lower ectobody, including thick thighs, plump butt and a dripping mound. 

“do you wish to be punished?” Blue whispered in Sans’s low voice that set Blue’s soul alight with desire. 

Stars, his datemate had such a sexy voice. He should ask Sans to talk to him like this more often!

“HNNGH! Y-YES! PUNISH ME LIKE I DESERVE! IT’LL BE _STRIKIN’_ ” 

Sans chuckled.

_SMACK!_

“AH!”

“now don’t forget to count for me!”

“O-ONE!”

_SMACK!_

“TWO.”

_SMACK!_

“TH-THREE!” 

Red shook and moaned as he tipped forward. Before he face planted into the carpet, Sans wrapped his arms around the other’s upper body and lowered the two of them onto the ground so that “Blue’s” butt was in full display. Sans maneuvered his hand around to remove the battle body that “Blue” wore, whispering praises.

“HEARIN’ MY OWN VOICE SAYIN’ DAT TO ME IS WEIRD AS FUCK-- OW!“

_SMACK! SMACK! SMACK!_

“what did i say about cursing?” _SMACK!_

Red whimpered as Blue caressed his own ecto-butt, the magic there already deepening to a dark blue. Good thing damages from ecto weren’t long-lasting or he’d be in a world of pain the next morning once back in his own body.

“if you apologize, i’ll treat you,” Blue said, reaching an arm over to swipe his phalanges along a dripping slit. 

Red moaned and thrust his hips forward, though Blue held him back. “PL-PLEASE! MO-MORE! H-HARDER!”

“gotta say, you’re pretty demanding, pal,” Sans said, squeezing “Blue’s” thigh.

Blue’s soul warmed at the sight of Sans’s participation. He had feared this whole bodyswapping sex thing would’ve been something that Sans wouldn’t enjoy, but the flushed, hungry grin told otherwise. 

“indeed he is, sans,” Blue replied. He then turned and kissed his boyfriend. “you still ok with continuing this?”

“totally. long as it’s ain’t me doing the hitting, i’m bonetastic.”

Red snorted, earning another loud slap. 

Sans cut Red’s pained yelp by smashing his teeth against the other’s. Meanwhile, Blue inserted the pointer and middle phalanges into his body’s pussy, vigorously stroking the tight walls. Red’s jolted between him and Sans. His moans were swallowed by Sans’s expert mouth. Blue raked his other hand down thick, blue ecto-thighs, leaving dark scratch marks. Red squirmed and tightened around his two fingers. 

Red and cyan tongues wrestled against each other between Sans and Red’s open jaws while Sans stroked the glowing crimson cock peeking through the black track shorts. 

“you’re so well behaved, red, you deserve a reward,” Blue said in Sans’ sultry tone. 

A pleading keen escaped from between Red and Sans’s open mouths. Red pulled away, panting and face completely flushed blue. Blue eye lights briefly flickered into hearts. 

“this is hot as hell,” Sans murmured. 

He pumped his length, fast and hard. A bead of red precum surfaced on the head. The sight made the dick within Blue’s pants to harden painfully. He slid out of Sans’s shorts with a groan, continuingly the rough fingering of his own cunt. He flicked and rubbed at the clit.

“FUCK!” Red howled as he came hard. 

Blue grinned as he withdrew his cum-covered phalanges from the still-clenching pussy and slapped his right buttcheek. 

“what did i say about cursing? we should clean that filthy mouth of yours, _ain’t that correct, “red”?_ ” Blue teased.

“that would be _dicklicious_ , heheh.”

“HNNGH, HAH~!”

Sans sat down against the bed’s headboard with legs spread outward, guiding “Blue’s” skull down to the glowing red member. Red panted and then licked a swipe upwards from the base to the top before taking the head into his mouth. Sans groaned and shallowly thrust his hips three times. 

Blue crouched behind Red. He ran a hand down the spaces between each vertebrae. He stopped before a puckered hole. With already slick fingers, Blue massage and inserted a finger inside. Red gave a muffled moan, “his” empty cunt clenching at nothing. Sans gasped, ruby tongue flopping out of his mouth. 

Blue watched his two counterparts with a heated gaze, halting his movements every few thrusts of his hand. Then he inserted a second finger. Lewd moans and pants filled the room, interspersed by Sans’s soft praises as Red took the entirety of his own thick dick into his mouth.

“hgh, so good, red, hah!” Sans panted as he shut his eyes and arched his back.

“stop!” Blue ordered.

Red immediately did as he was told, wrenching a whine from Sans. Blue pulled Red off and backwards into his arms. Blue leaned back until the tip of “his”—rather, Sans’s— cock pressed against “Red’s” back entrance. 

“you think you can take your own and sans’s phallus, red?” 

“F-FUCK YEAH!” Red ground back against Blue, who shuddered. “ _CUM_ TAKE ME, SWEETHEART.” He winked at Sans.

Sans burst out in a bout of laughter. He crawled over to “Blue’s” diminutive form and lined the crimson cock against the quivering cyan cunt.

“ _reddy_ or not, here i _cum_.”

Sans plunged in simultaneously with Blue. Red screamed and fisted the bedsheets. The two stopped to give time for Red to adjust. Blue moaned at how great it felt. 

Was he always this tight? Stars, he should screw himself more often!

Once Red gave them a nod to continue, Blue slammed back in as Sans pulled out. They continued on this alternating fashion. Blue exclaimedt both Red and Sans’s names in bliss. The other two did the same. Heated cries of pleasure mixed with the squelching of their lovemaking filled the room. 

A brilliant flash of cyan and white fluttered before their sight. Blue’s radiant soul hovered in between Red and Sans. Both skeletons watched with open amazement.

“shit, blue, your soul’s beautiful,” Sans muttered.

Blue blushed, giving Sans a pass on the cursing this time. He gave Sans an inquiring raise of the bone brows, which Sans returned with a faint nod. 

Another flash of blue and white flickered before them three, revealing Sans’s soul. It was a bit dimmer than Blue’s own, but nevertheless, Blue found it simply hypnotizing. When Sans and Blue turned their attention to Red, he shook his head in embarrassment. The two didn’t press.

“let’s keep plowing along, heh,” Sans said, giving a hard thrust.

Red released a shuddering breath. “YES! KEEP MOVIN’!” he commanded, heated and needy.

Blue smirked as he withdrew “his” dick to its tip and plunged back in at the same time as he spanked Red hard in the ass. Red closed his eyes and screamed in pleasure. This was quickly followed by Sans kissing Red deeply. A faint reddish, pink glow emerged. Blue saw the barely visible outline of an inverted heart inside Red’s ribs. Although it shone the dimmest, Blue still loved it with all his being.

“red, bl-blue, hnngh, y-you both feel, amazin’,” Sans praised as he tenderly pulled in and out of “Red”, slow and steady.

Blue, meanwhile, went hard and fast, Red’s wanton cries only spurring him on. He even leaned over unmarred collarbone and bit down. Tears dotted the corners of Red’s sockets and his eyelights morphed into hearts. Their three souls drifted together and fused together.

Their love and passion hit like a bus.

“sans! red!” Blue cried out as he came.

Sans came not a second later, and Red followed after. When Blue opened his eyes— since when had he closed them?— he found himself trapped between Sans and Red. The area where he’d bitten himself stung, but not painfully so. 

“that was amazin,” Sans slipped out of Blue’s pussy with a wet squelch.

“fuck yeah we should, narcissism be damned,” Red answered in his own voice. 

Blue gave a final slap at Red’s pelvis— not his own this time— who yelped. 

“WATCH YOUR LANGUAGE, RED. AND NOT A SINGLE PUN FROM YOU, SANS!”

“aw, how’ja know it was coming.”

Blue responded by kissing the two boneheads.

“BECAUSE I LOVE YOU. AND YOU TOO, RED!”

“love ya both too.”

“geez, yer both mushy snowpoffs.” Red grinned and reciprocated the gesture. “but yer my mushy snowpoffs.”

The three of them fell asleep in each other’s arms.


End file.
